Aspects of the present invention relate generally to the field of biosensor design, and more specifically to the design of a blood glucose test strip.
In a blood glucose metering system, a conventional test strip typically employs a venting hole on the cover layer of a test strip. For example, as shown in FIG. 1, the test strip consists of a cover layer 100, a spacer 200 and a base layer 300. Typically, the spacer 200 is sandwiched between the cover layer 100 and the base layer 300. Once the spacer 200 is combined with the cover layer 100 and the base layer 300, a channel 210 is formed, and the blood can flow from the opening of the channel 210 to the reaction area. In order to facilitate the blood flow inside the channel 210, the bottom surface of the cover layer would be hydrophilic in order to facilitate capillary motion inside the channel. In addition, to further facilitate the blood flow, the cover layer 100 comprises of a venting hole 110 such that, when the blood enters the channel, air can exit through the venting hole 110.
A problem in regard to the previous configuration is that forming the venting hole 110 on the cover layer 100 limits the strip's design flexibility. Moreover, because the blood may stop flowing once reached the venting hole 110, the venting hole 110 will have to be placed after the reaction zone, thereby further limiting the design flexibility. In addition, the blood may sometimes flow through the venting hole 110, thereby causing possible contamination.
Accordingly, there is a need for a design allowing air to exit the channel through lateral sides of the blood glucose test strip, without adding significant manufacturing complexity.